Controlling mechanism for automobile transmissions



Jan. 10, 1939. 5 LlNcoLN 2,143,446

CONTROLLING MECHANISM FOR AUTOMOBILE TRANSMISSIONS Filed Feb. 23, 1937 4Sheets-Sheet l 5 Q l g 3 V k I 1 H: :2: r\ $9 7 'l' I n INVENTOR.

A4274 5? l/NcoL/v Jan. 10, 1939. N. s. LINCOLN CONTROLLING MECHANISM FORAUTOMOBILE TRANSMISSIONS Filed Feb. 25, 1957 4 Sheets-Sheet 2 4 0 v I trETTTIII. :3 VI A 5G 4 3/ 24 N A a; INVENTOR, NEIL 5. NCOLN Jan. 10,1939.

CONTROLLING MECHANISM FOR AUTOMOBILE TRANSMISSIONS Filed Feb. 23, 1937 4Sheets-Sheet 3 INVENTOR.

g? S. LINCOLN //1 s ATT RNEYs N. s. LINCOLN 2,143,446

Jan. 10, 1939. s LINCOLN 2,143,446

CONTROLLING MECHANISM FOR AUTOMOBILE TRANSMISSIONS Filed Feb. 23, 1957 4Sheets-Sheet 4 INVENT OR. IVE/L 5. L/A couv. BY gen xzl Mug H iATTORNEYS.

Patented Jan. 10, 1939 UNITED STATES PATENT OFFICE CONTROLLING MECHANISMFOR AUTOMO- BILE TRANSMISSIONS corporation of Ohio Application February23, 1937, Serial No. 127,188

7 Claims.

This invention relates to controlling mechanism for automobiletransmissions, and more particularly to an improved control mechanismfor vacuum actuated shifting means for automotive multi-speedtransmissions.

Heretofore, automotive vehicles have been provided with a multi-speedarrangement in association with the rear axle and in addition to theregular transmission whereby the ratio of axle speed to engine speed maybe altered after the vehicle has acquired a desired speed. The rear axlespeed has usually been limited to two-speeds relative to the drive shaftspeed and the change from one speed to the other has been effectedthrough suitable gearing and/or clutch arrangements. The shifting of thegears and/or clutches has been effected either manually through suitablelink means or by utilizing the engine vacuum under a manual control.

A two-speed axle drive transmission utilizing the engine vacuum undermanual control is illustrated in U. S. Patent No. 2,071,165, issuedFebruary 16, 1937 to George W. Harper and Alfred R. Catto, entitled Axledrive transmission. Transmissions of the type illustrated in theaforementioned application have a manual control lever located on oradjacent the vehicle dashboard for shifting from one axle speed toanother but this necessitates employing one hand for this purposeleaving only one hand for guiding the vehicle or preventing the use ofthis hand for operating the brake or for similar purposes. It is highlydesirable that both hands be left free for the normal operation of avehicle employing a two-speed axle drive transmission and to this end, Ihave devised an improved control mechanism for vacuum operatedtransmissions of this type whereby a supplemental clutch movementcontrols the operation of a vacuum system and eliminates the necessityof employing either hand for this purpose. I

It is an object of my invention therefore to provide an improved controlmechanism for fluid operated multi-speed axle drive transmissions.

Another object of my invention is to provide an improved controlmechanism for fluid operated multi-speed axle drive transmissions whichrequires only a supplemental clutch movement and eliminates thenecessity for additional control levers mounted on the vehicledashboard.

Another object of my invention is to provide an improved arrangementoperable by pedal movement for controlling mechanisms actuated by thevacuum system of an internal combustion engine.

Another object of my invention is to provide a signal means formulti-speed axle drive transmissions indicating a particular ratio ofaxle speed to drive shaft speed.

Another object of my invention is to provide a multi-speed axlemechanism for automotive vehicles having means associated therewithadapting the speedometer for the vehicle to read correctly according tothe axle speed.

Another object of my invention is to provide a control mechanism forfluid operated multispeed axle drive transmissions including meansrendering the control mechanism inoperable to effect speed change belowa pre-determined drive shaft speed.

Other objects of my invention and the invention itself will becomeincreasingly apparent from a consideration of the following descriptionand drawings wherein:

Fig. 1 is a diagrammatic view of an automotive vehicle embodying myinvention;

Fig. 2 is an enlarged section taken along line 2--2 of Fig. 1;

Fig. 3 is a top plan view of a distributing valve which I employ with acover portion shown in section;

Fig. 4 is a section along line 44 of Fig. 3;

Fig. 5 is a. left end elevational view of the valve of Fig. 4 with thecover portion shown in section;

Fig. 6 is a fragmentary sectional view taken along line 6-6 of Fig. 5;

Fig. 7 is a revolved sectional view taken along planes 'I-! of Fig. 3;

Fig. 8 is a vertical sectional view taken along line 88 of Fig. 4;

Fig. 9 is a fragmentary sectional view showing an electrical contactmechanism I may emp y;

Fig. 10 is a fragmentary right hand elevational view of the valveillustrated in Fig. 4;

Fig. 11 is a fragmentary elevational view, partially in section of agovernor control mechanism which I may employ, and

Fig. 12 is transverse sectional view through a drive shaft showing aportion of the mechanism of Fig. 11.

Referring now to the drawings, I have illustrated generally at I!) theintake manifold of an internal combustion engine of a vehicle and whichin a well known manner will intermittently create a vacuum or suction inany conduit connected therewith due to displacement of air in a cylinderby the upward movement of the piston and the reverse piston movementcreating a substantial vacuum within the cylinder. Connected with theintake manifold I0 is a copper or the like vacuum-tube II, theconnection being preferably made by a flexible coupling connecting theend of tube Ii with a lateral outlet from the intake manifold. This typeof connection eliminates any tendency toward breakage due to vibration.

The vacuum tube I I connects with a distributing valve generallyindicated at I2 and which will be hereinafter described. Thedistributing valve l2 may be conveniently mounted inside the enginecompartment by securing the valve to a bracket indicated at i3. Leadingfrom the distributing valve l2 are two vacuum lines l4 and I5 preferablyformed of copper, the lines l4 and I5 passingbeneath the floor of thevehicle and connecting with a vacuum cylinder l6 adjacent the rear axle.The connections for the vacuum lines throughout preferably compriseflexible tubing to eliminate any tendency toward breakage and- Ipreferably provide a considerable length of flexible tubing for lines I4and I5 adjacent cylinder l8, as indicated at H.

'The rear axle, generally indicated at I8, is of the two speed type andthe change from one axle speed to another is efiected through the vacuumcylinder IS. A preferred form of rear axle two-speed construction ofthis type being illustrated and described in the aforesaid Patent No.2,071,165 issued February 16, 1937, entitled Axle drive transmissions.The operation is effected by creating a substantial vacuum on one sideof a piston within cylinder l8 while subjecting the opposite side toatmospheric pressure thereby forcing the piston in a given direction toalter the gearing arrangement of the rear axle relative to the driveshaft. The reverse operation is effected to change the speed, that isthe vacuum line is connected with the side of the piston whichpreviously was subjected to atmospheric pressure and atmosphericpressure is admitted to the former vacuum side of the piston. Althoughthe piston is operated by a vacuum line arrangement it is apparent thatthe pressure differential at opposite ends of the piston effectingpiston movement could be provided by compressed air or fluid pressure.

The distributing valve I2 is adapted to control the air and suction inthetwo lines l4 and I 5 which lead to opposite sides of the piston, andthe valve operation is controlled by a supplemental motion of theordinary vehicle clutch pedal. The clutch pedal is generally indicatedat 20 and is pivoted in the usual manner, as indicated at 2|, with thepedal portion extending through the floor board and accessible in theusual manner to pedal movement of the operator. The normal clutchmovement adapted to disconnect the drive shaft with the engine isindicated by N and an additional movement indicated at D is adapted tocontrol operation of the distributing valve. The clutch is provided witha generally depending arm 22 of relatively short length to which issecured a link rod 23, the opposite end of the link rod engaging anelement 24 pivotally supported by the distributing valve as indicated at25. During normal movement of the clutch pedal corresponding to N, thecam surface of element 24 indicated at N moves about an axis 25 as acenter and has no effect on the operation of the distributing valve.However, when the clutch pedal moves through D, the valve I2 is operatedin a manner to be described.

The operation of the distributing valve l2 which is best illustrated inFig. 4, will now be described. The element 24 actuated by the clutchpedal, as previously described, is integrally locked with a shaft 30rotatably mounted in spaced bearings 3i-3i formed on the distributingvalve l2. Integral with shaft 30, is a generally vertically extendingpin 32 to which is pivotally secured the yoke portion of an arm 33whereby the arm 33 will be oscillated vertically as the shaft 30 isactuated and will also be permitted to move horizontally about pin 32 asa center, thereby effecting a universal movement.

Arm 33 in Fig. 4 is shown in elevated position as indicated at 33' orthe position it will occupy during normal clutch operation. The fullline position indicates the location of arm 33 when the clutch pedal hasbeen forced downward and stopped by engagement with the vehicle floor.

In the full line position, either of two lateral ears 3434 provided onarm 33 engage a slideable pin 35 to force it vertically downwardly andthereby force a ball valve 36 from engagement with a generallyfrusto-conical valve seat 31. The downward movement of ball 361sresisted by a spring 38 which seats upon a cup-shaped washer 39 which isin air-tight engagement with the walls of a. chamber 40 within which the,ball valve is disposed.

An upwardly extending stem 4| connecting with chamber 40 is acontinuation of conduit H whereby suction created in the motor intakemanifold will efiect a substantial vacuum in chamber 40 assuming ballvalve 36 is in open position. The suction effect on chamber 40 will onlycontinue during the time the ball valve 36 is held in open position orduring the relatively short period when the clutch pedal is held againstthe floor board thereby only placing an additional suction load on theengine for the short interval necessary to effect movement of the pistonat the rear axle.

In order to prevent the clutch pedal from effecting a speed change atthe rear axle during normal operation thereof, a stop means or detent isprovided which will now be described. Referring particularly to Fig. 6,it will be noted that element 24 is provided with a camming portion Dwhich is adapted to engage the V-shaped portion of a detent 42 slideablymounted in a sleeve 43 formed integral with the distributing valvehousing. A relatively stiff compression spring 44 constantly urges thedetent in a direction to engage element 24 whereby the operator isinstantly aware of the termination of normal clutch movement whenpressing the clutch pedal toward the floor due to the resistance tofurther downward movement caused by the detent 42 engaging the portionD' of element 24.

The manner of utilizing the vacuum formed in chamber 40 to effectmovement of the actuating piston in vacuum cylinder [6 associated withthe rear axle will now be described. Referring particularly to Figures3, 4 and 8, it will be noted that the distributor valve housing isvertically bored to provide parallel cylinders indicated at 45 and 46within which are disposed piston valves 41 and 48 respectively. Thesepiston valves are actuated by movement of arm 33 in a downward directionconcurrently with opening of ball valve 36 to apply suction to chamber40. The upper end of piston valves 41 and 48 are provided with externalannular grooves which receive pins 49 and 50 secured to lateralextensions of a cam element 5|. The cam element 5! comprises a hubportion 52 through which is projected a of the clutch pedal the arm 33will be.elevated in some position such as indicated at 33', Fig. 4. andwill be maintained substantially centrally of the distributing val e bymeans of .a U-form leaf spring53 having and portions adapted to forcearm 33 toward acentralposition when elevated out of contact with camelement Referring now to Figs. 4 and 8 wherein arm 33 is shown at anelevated position as indicated at 33', it will be app rent that as theclutch pedal-is forced downwardly that the arm 33 will correspondinglybeforced downwardly ,to ride along the left"hand camming surface," andeventuallyengage pocket 51and thereby tilt cam element 5| in a counterclockwise' direction forcing piston valve 41 downwardly, and pistonvalve 48 upwardly. -An eccentric arrangement aids in l this movementafter the apex of the camming i portion 55 haspa'ssed theverticalcenterand of the clutch pedal or when 'the cluteh maintains the cam element5iin-the oscillated 2 position upon raising of lever 33 due to normalfunctioning of the clutch pedal. This eccentric arrangement comprisesadepending sleeve .50 provided on cam element 5| within which isslideably disposed a cup shaped member 5| engaging i acompressed spring52.

The base of member 5| has a semi spherical depression formed therein toengage the spherical end of a pin 63', the

opposite end of pin 53 being similarly mounted in a semi-sphericalpocketformed in a portion of the distributor valve housing. It will now beunderstood that uponthe cam element 5| being forced on either side of amedian position through engagement with arm, 33,..that a snap actionefiectjwill occur and maintain one of the piston valves in an elevatedposition and the other valve in a lowered position. During norrnaloperation pedal is moving through the distance N, as illustrated in Fig.1, the shaft 30 and arm 33 will be rocked but thetravel of .thearm 33downwardly is not suflicient-to engage the pockets 51 or 58 of cam 5| torock. the cam ,to a reverseposition. It will be understood that afterthe cam has: been tilted-to the position illustrated in Fig, 8 throughengagemerit of arm 33 with pocketfl of the cam, that the arm 33willJbelifted above andiclear of'cam 5| when the clutch pedalisreleasedto engage the clutch. One of thespring arms 59 is always inengagementiwith arm 33' tending to return the arm to a central positionand this occursas soon asthe arm is lifted to a position above cam 5|,thereby placing the arm in position to engage cam pocket 51 when nextthe clutch pedal is pressed inwardly beyond the distance N.

Fig. 7is a section taken along planes ,'|-.-1 of Fig. 3' and revolvedinto a common planeand it will be noted that a diagonally disposed'port65 affords communication between chamber 40 and cylinder 45 anda similarport65 affords communication between. chamber and cylinder-46. Adjacentthe top of cylinders 45 and 45 are ports 51-43! communicating with theatmosphere whereby atmospheric to the cylinders.

:side to effect" piston movement.

fvehicle operator that the e through the carn' operating upper annulargroove of pressure may be admitted" Ports indicated at 58 and 59 formedin cylinders 45 and 45 respectively communicate with vacuum lines It andi5 leading to the vacuum cylinder l6 whereby in a manner to be nowdescribed suction may be applied to one side of the piston within thevacuum cylinder and atmospheric pressure concurrently applied to theopposite side of the piston thereby effecting piston movement andresultantly, speed change.

Referring now to Fig. 7, it will be noted that piston valve 41 is inraised position and covers port 55 thereby eliminating any suctioneifect from chamber and at. the same time port 51 is uncoveredpermitting atmospheric pressure within the cylinder which, in tum, iscommunicated and thereby subjects the cylinder 43 to suction wandthroughport 53 this suction is communicated .toline l5 and then tothe-opposite side of the piston while at the same time atmospheric pressure is prevented-from communicating with port 69. ,Ihus, it willbeunderstood that downward movement of the clutch pedal beyond a prede-.termined normal operating position will actuate cam element 5| througharm 33 and resultantly communicate vacuum to one side of the actuatingpiston and atmospheric pressure to the opposite Upon the release of theclutch pedal from the extreme downward position to normaloperatingposition, ball valve 36 will besealed with its seat 31eliminating any further suction dragon the engine, but the cam element5| and its,associated piston valve will remain in operated position.

denced by the detent l2 resisting movement be yond the normaldisengagement position and this additional movement rocks shaft and arm33 which has been extended above cam element 5| ,,downwardly asui'ficient amount to engage the right hand camming surface 55 as viewedin Fig. I Band eventually pocket 58 to effect a snap action This lowerspiston valve 4'! and raises piston valve 48 thereby in a similarmanmovement.

ner communicating atmospheric pressure to the piston face whichpreviously has'been subjected to vacuum and: applying suction to thepiston face whichpreviously has been subjected to"atmosphericpressureresultantly moving the piston in a reverse directionto effect the speed change.

T he spring .controlleddetent 42 is provided j mere ly to oifersuflic'ient resistance. to inward When it is desired to again change therear movementof theclutch pedal to indicate to the range. Thus, there isno danger of the operator pressing the clutch pedal downwardlysufliciently far to effect speed external wall of the distributor valve,housing andis provided'with a laterally extending lug projected througha slot in a cover H to engage the piston valve 41 whereby bar 10 will bevertically moved in correspondence with movement of valve 41. Bar 10 isrecessed clutch pedal is moving A;

to receive electrical insulating material 12 withlnwhich-is seated acontact strip 13. A generally U form housing element 14- formed ofsuitable electrical insulating material encases bar 10, the elementbeing widened laterally whereby screws "A may be projected therethroughand engage the distributor valve housing to secure element l4 thereto.Element I9 is also relatively thickened to provide spaced recesseswithin which are disposed headed contacts 15 and I8 resilientlymaintained in contact with bar I8.

' Bridging of contacts 15 and I8 by contact strip 13 energizes a circuitincluding wires 11 and a sig nal light 78 mounted on the dashboard.Thus, when the circuit is energized and indication is given that aparticular one of the two speeds is being used in operating the vehicle.

Securedto the top of bar 18 is an eye bolt 19 to which a wire 88 may besecured and the opthe adapter to change the speed indication when thepiston'valve 41 is forced downwardly.

It is desirable that positive engagement of clutch elements associatedwith the drive shaft and rear axle when changing speeds be delayed untilthe speeds of the rear axle and drive shaft be synchronized and a meansof effecting this result is described in the forementioned Patent2,071,165. Otherwise, serious damage might re- 4 suit to the mechanismparts. With the present arrangement it is desired to prevent attemptedspeed change when the vehicle is not moving but with the engine idlingsufliciently to create vacuum in the cylinder l8 or until the vehiclehas attained a pre-determined speed. To prevent operation of the speedchange mechanism under these conditions I provide a governor controlarrangement best illustrated in Figs. 1, 11 and 12.

A valve mechanism 82 is inserted in the vacuum line II which connectsthe intake manifold ID with the distributor valve II. The mechanism 82comprises a two part housing 83, each part including a neck portionadapted to sealingly engage confronting end portions of line H, and theparts then being relatively telescoped and sealed by suitable material8|. A butterfly type valve 85 is mounted within housing 83 and isrotatable on trunnions having bearing in the housing walls, one of thetrunnions being projected through the wall and fixedly secured to an arm88 disposed internally of the housing. The outer end of arm 88 has atension spring 81 secured thereto continuously urging valve 85 in aclosing direction. Also secured to the outer end of arm 88 is one end ofa link element 88 which is illustrated in Fig. l as a wire rope and inFig. 11 as a rod but any suitable link arrangement may be used. Theopposite end of element 88 is secured to a governor mechanism 89.

The governor mechanism 89 is illustrated as being operable from a shaft98 associated with a conventional speedometer actuating mechanism. Theconventional speedometer actuating mechanism usually comprises a worm 9|keyed to the splined portion of the vehicle drive shaft 92 adjacent thetransmission. The drive shaft housing has mounted thereon an auxiliaryhousing 93 forming bearing support for shaft 98 and encasing a gear 94meshed with worm 9i and keyed to shaft 90. The speedometer actuatingmechanism so far described is of a standard construction and constitutesno essential part of my invention. I extend shaft 90 externally ofhousing 93 and key a disc 95 thereto and enclose the disc 95 in atwo-part housing 98 whose inner walls are slightly spaced from the disc.Heavy oil or similar fluid is forced within the housing 98 through anopening 91' which is then plugged. Housing 98 is provided with an arm 98to the outer end of which is secured the link element 88.

The operation of the governor mechanism will now be described. When thedrive shaft 92 is at rest, spring 81 will maintain valve 85 closed andif the vehicle operator should press the clutch downwardly beyond thenormal operating position ball valve 38 of distributor valve I2 would beforced from its seat 3! but since the vacuum line H is closed nomovement of the piston within cylinder l8 would result. When the driveshaft starts to rotate the frictional drag of disc 98 causes arm 98 tomove in a counter-clockwise direction as viewed in Fig. 11 and operatethe link element 88 against the tension of spring 81 to open valve 85. Iprovide a stop 99 engageable by arm 88 to limit movement after the valveis opened a maximum amount, and housing 98 will be restrained fromfurther movement. Thus, at any time after the car is in motion the speedchange may be effected as described.

Although for illustration I have shown the above described governorarrangement, I contemplate that any suitable governor operable at apredetermined speed of the vehicle to open valve 85 may be employed.Governors of this general type are well known in the art.

Although I have shown and described a pre ferred embodiment of myinvention I contemplate that numerous and extensive departures may bemade therefrom without departing from the spirit of my invention and thescope of the appended claims.

Having thus described my invention what I claim is:

1. In a vehicle driven by an internal combustion engine of the typehaving a multi-speed rear axle and including a vacuum cylinder andpiston effecting speed change, a valve mechanism controlling pistonmovement comprising a conduit connection with the engine intakemanifold, means normally checking suction from the engine to the valvemechanism, a pair of conduits connecting the valve mechanism with thecylinder at opposite'ends of the piston, valve means associated withsaid mechanism adapted to concurrently admit air to one of said conduitsand apply suction to the other to effect piston movement, pedal meansfor operating the valve means to successively move the piston in reversedirections, and movement of the pedal means to operate the valverendering the check means inoperative.

2. In a vehicle having a motor adapted to create suction in an iiitakemanifold and having pedal means disconnecting the engine and driveshaft, the vehicle having a multi-speed rear axle including a vacuumcylinder and piston for effecting speed change, a valve mechanismincluding a connection with the engine intake manifold, means normallychecking suction from the engine intake manifold to the valve mechanism,a pair of conduits connecting the valve mechanism with the vacuumcylinder at opposite ends.

of the piston, valves adapted to concurrently and selectively admit airto one of said conduits and apply suction to the other from the engineintake manifold, the valves being operable by the pedal means throughsupplemental .movement beyond normal movement disconnecting the ensineand drive shaft, and means connecting the pedal means and check meansoperable on movement of the pedal means to a valve operating position torender the check means inoperable.

The combination with an automotive vehicle having a multi-speed rearaxle, speed change means operable by fluid pressure, a clutch pedalmovable to disconnect the vehicle engine and drive shaft, means forproviding differential fluid pressure, a valve mechanism operable tocontrol the application of differential fluid pressure to the speedchange means for effecting speed change, said valve mechanism comprisinga low pressure fluid chamber, a pair of slide valves each operablewithin an individual chamber in the valve mechanism, a pair of conduitscommunicating with the speed change means and valve chamber portsconnecting the low pressure chamber with each valve chamber, portsconnecting each valve chamber with a source of relatively higher fluidpressure, and means for concurrently operating the valves by continuedclutch pedal movement in a given direction after the engine and driveshaft are disconnected to cause the port of one valve chamber from thelow pressure chamber to be closed and a high pressure port to be openedand the port from the low pressure chamber to the second valve chamberto be opened and the high pressure port to be closed.

4. The combination with an automotive vehicle having a multi-speed rearaxle, speed change means operable by fluid pressure, clutch pedalmovable to disconnect the vehicle engine drive shaft, means operable bythe engine for eflecting sub-atmospheric pressure, a valve mechanismoperable to control the application of difl'erential fluid pressure tothe speed change means for effecting speed change, saidvalve mechanismcomprising a chamber communicating with the engine for effectingsub-atmospheric pressure therein, a pair of valve chambers each incommunication with said-chamber, each oi said valve chambers beingvented to atmosphere, conduits connecting each of said valve chamberswith the speed change means, slide valves in each of said chambers forselectively closing the atmospheric vent and communicating with the lowpressure chamber, means interconnecting the valves for concurrentlyoperating the valves to apply atmospheric pressure to one conduit andsub-atmospheric pressure to the other conduit, means operable by clutchpedal movement beyond a ential fluid pressure, of means for actuatingsaid unit comprising a valve mechanism having a pressure chamber, a pairof valves operable to concurrently supply relatively low and highpressure fluid to the control unit, communicating means between each ofsaid valves and the pressure chamber, communicating means between eachof said valves and a source of substantially constant fluid pressure,valve means for the chamber operable to efiect a fluid pressure in thechamber different from said substantially constant pressure, and meansoperable by the ve hicle operator for concurrently operating the chambervalve means, and the pair of valves to supply a differential fluidpressure to the control unit.

6. The combination with a speed control mechanism for motor vehicles andthe like having variable speed gears, and a control unit for said gearsoperable by differential fluid pressure, of

means for actuating said unit comprising a valve mechanism having a lowpressure chamber, a pair of valves operable to concurrently supply highand low pressure to the control unit, communicating means between eachof said valves and the low pressure chamber, communicating means fromeach of said valves to a source of relatively higher fluid pressure, aconduit communicating with the vehicle engine and low pressure chamberfor effecting relatively low pressure in the chamber, a first valvemeans for said conduit closing the conduit until a predetermined vehiclespeed is attained, a second valve means associated with the valvemechanism and normally closing the conduit, and means operable by thevehicle operator for concurrently operating the second valve means andactuating said pair of valves to transmit low pressure fluid from thelow pressure chamber and high pressure fluid from the high pressuresource to the control unit when the vehicle is operated above saidpre-determined speed.

7. In a vehicle having an internal combustion engine including an intakemanifold and a clutch pedal movable to disconnect the motor and driveshaft, the vehicle including a multi-speed rear axle and a pistonmovable within a cylinder to efl'ect speed change, a valve mechanismcomprising a.chamber connected with the engine intake manifold, meansfor normally checking suction to the chamber from the intake manifold,means operable by the clutch pedal on continued movement after clutchdis-engagement to render the check means inoperable, a pair ofconduitscon- ,necting the valve mechanism with the cylinder at oppositesides of the piston, valve means associated with the conduits adapted toconcurrently admit atmospheric pressure to one conduit and apply suctionfrom the chamber to the other conduit, means linking the clutch pedalwith the valve means whereby clutch pedal movement beyond a normalposition disconnecting the engine anddrive shaft will concurrentlyrender the check means inoperable and thereby applying suction to thechamber and actuate the valve means to apply suction to one side of thepiston and atmospheric pressure to the opposite'side effecting pistonmovement and resultantly speed change at the rear axle, and meansproviding for maintaining the valve means in actuated position uponreverse movement of the clutch pedal eflecting connection of the driveshaft with the engine.

NEIL B. LINCOLN.

